A strainer is an essential accessory for the proper functioning of your bilge pump and will allow to evacuate the water that stagnates in the boat while preventing debris from getting stuck in the hose and the pump.
A strainer can be made of plastic or brass and is connected directly to the bilge pump by a hose. It is a filter that will prevent the pipe that discharges the water from becoming blocked with debris. In most cases, the strainer is combined with a check valve that ensures a one-way flow of water, thus preventing backflow of water into the bilge.
The strainer can have a horizontal or vertical outlet facing right or left. It can also have a different diameter. You must therefore choose the version that best suits your hold and the pipe already installed (19, 25 or 38 mm diameter...).
A marine brass strainer will have an anti-fouling stainless steel screen and will be heavier than a plastic strainer, allowing it to remain in position without screws at the bottom of the hold.
For your bilge pump to work properly, it is best to limit the length of the discharge and suction lines. Ideally, the hose between the pump and the hull inlet should not exceed 1 meter. It is also best to install only one pump per discharge line. Finally, it is essential to regularly clean all bilges to avoid debris blocking the flow between the bilges. Sand and hair can pass through the strainer and damage the pump.
As you can see, the bilge pump allows you to evacuate the water that stagnates in your bilges and to keep your boat afloat in case of water ingress (by checking beforehand where the leak comes from and by making the necessary adjustments). It is essential that the non-return valve on the strainer works. If it is not, it will be impossible to evacuate the water correctly. If you have a problem with the electric bilge pump and your strainer, there is always a manual bilge pump on a boat that you can operate to drain the water from the bottom of your bilges!
